When digital binary-coded information is transmitted, one task is to obtain the transmitting clock of the distant data source at the receiving station with same frequency and phase relation. Ony then it is possible to scan the received data in the middle of the sign for obtaining their information for further handling and computing with a definite clock timing. A synchronization can also be achieved by transmitting additional synchronizing signals together with the binary-coded signals containing the information. But the number of signs which must be transmitted is increased which might cause the need of a higher transmission speed.
Therefore it is more reasonable to obtain criteria for synchronizing out of the data themselves as it is known from German Patent Application No. DE-AS 12 87 609. The method described therein and the means for step-synchronisation in synchronous transmitting systems provide a control circuit which is feeded with a higher or a lower frequency in depence of the phase relation between the received signal and a frequency generated by a clock generator for controlling a divider chain. Therefore means for generating comparison pulses are provided by which the control unit is switched over to higher frequency when a comparison pulse occurs. The higher frequency is thereby directly generated by a frequency generator and the lower frequency is obtained by a bistable divider. Normally the lower frequency is applied to the clock divider chain, and only if a regulation is necessary the higher frequency is switched to said control circuit. Then the stepping of the divider chain is speeded up whereby the phase relation is changed positively. Pulses of half the frequency are applied to the divider chain for delaying the phase relation when a comparison pulse occurs again.
By this known method the synchronisation is done totally digital whereby the clock generator itself is not influenced. Therefore a synchronisation is possible only by steps which are given by the clock frequency and the double frequency which is generated by the frequency generator. Moreover the output signal of the arrangement could be changed in an undue way if the received signal contains gaps, because the actions of synchronisation cannot be stopped in time.